WASHINGTON — Researchers, announcing a scientific breakthrough, said Monday they have altered the genetic makeup of laboratory mice to produce a human protein that could give rise to an inexpensive treatment for heart attack patients.
The genetic engineering technique involved introducing a human gene into the makeup of mice, so that the milk they produced contained the human protein TPA, an anti-clotting agent believed to benefit heart patients. Similar techniques could lead to alterations of cows and goats to make their milk a cheap source of other important drugs, the researchers said.
The development would make it much cheaper and easier to manufacture human proteins such as TPA, and it could become the basis of a billion-dollar drug industry.
First Lab Demonstration
"This is something people have been talking about for years, but this is the first demonstration that it can really work," Harvey Bialy, research editor of the scientific journal "Bio/Technology" in New York, said in a telephone interview. The journal's November issue will outline the findings of the research, which was announced in a briefing by the project co-sponsors, the National Institutes for Health and Massachusetts-based Integrated Genetics Inc.
The breakthrough is "particularly timely" in light of recent fears that the United States was lagging behind Europe in such areas of genetic engineering, said Alan Smith, vice president of Integrated Genetics.
"If in fact this process would work as they're saying, it would be revolutionary," said Harold Silverman, president of the National Assn. of Pharmaceutical Manufacturers in New York.
In the study, researchers fused part of the human genetic coding that produces TPA with genetic material in mice that regulates milk protein production. The hybrid gene was then introduced into surrogate-mother mice, and many of the offspring born with it secreted TPA in their milk.
Researchers at Integrated Genetics will now try to get the same results in goats, which could produce the protein in larger, commercially valuable quantities.
TPA, hailed as the "penicillin of heart attacks," is a blood-clot dissolving protein that is found naturally--but in low levels--in human blood. It was found to be an effective treatment in tests on 4,000 heart attack patients, but has been used only experimentally.
The Food and Drug Administration is reviewing an application from Genetech Inc. of South San Francisco to produce the TPA protein through an expensive, synthetic method for widespread use.
NIH and Integrated Genetics researchers said that the potential uses of the new genetic process are not limited to heart disease. Proteins to aid hemophiliacs, as well as industrial enzymes used in food processing, detergents and other products, might also be produced in animals, said Dr. Katherine Gordon of Integrated Genetics.